Derivative Instruments - Effect of Derivative Instruments on Statements of Income and Expenses (Detail) - Currency Futures Contracts [Member] - Not Designated as Hedging Instrument [Member] - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Futures contracts, realized gain (loss)	$ (11,617,887)	$ 6,743,928	$ (36,671,680)	$ 8,238,448
Futures contracts, unrealized gain (loss)	(2,916,978)	5,787,029	2,989,942	7,859,229
Future Contracts, Net Realized and Unrealized Gain (Loss)	$ (14,534,865)	$ 12,530,957	$ (33,681,738)	$ 16,097,677